Fingerless Gloves: Not sure, Mods will cover this anyway
Music on Foot: They took it out of the game for a reason, at a late stage though, so perhaps code is still there, once again, mods
More Minigames and Activities: Doubt this, would require a lot more time and effort to come up with new material
Removed Features: There ARE no removed features, this is a completely different engine from San Andreas, the features were not there to begin with.

There are removed features. By removed features, I mean those that were taken out during development, and was there during the Beta versions, implemented in whole or in part. Those that were in San Andreas and not in GTA IV, well, I couldn't care less anyway. Just hope that R* mades this PC version the version of GTA IV that was meant to be played. The console versions just had many things removed, mainly due to these features being incomplete, I think. But they have more time now, finish it up!